From: Asim Viladi Oglu Manizada <manizada@pm.me> mainline inclusion from mainline-v7.0-rc7 commit fda9522ed6afaec45cabc198d8492270c394c7bc category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/14175 CVE: CVE-2026-31402 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- When a compound request such as READ + QUERY_INFO(Security) is received, and the first command (READ) consumes most of the response buffer, ksmbd could write beyond the allocated buffer while building a security descriptor. The root cause was that smb2_get_info_sec() checked buffer space using ppntsd_size from xattr, while build_sec_desc() often synthesized a significantly larger descriptor from POSIX ACLs. This patch introduces smb_acl_sec_desc_scratch_len() to accurately compute the final descriptor size beforehand, performs proper buffer checking with smb2_calc_max_out_buf_len(), and uses exact-sized allocation + iov pinning. Cc: stable@vger.kernel.org Fixes: e2b76ab8b5c9 ("ksmbd: add support for read compound") Signed-off-by: Asim Viladi Oglu Manizada <manizada@pm.me> Signed-off-by: Namjae Jeon <linkinjeon@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com> Conflicts: fs/smb/server/smb2pdu.c [Commit 0066f623bce8 ("ksmbd: use __GFP_RETRY_MAYFAIL") change the way to alloc smb_ntsd.] Signed-off-by: Li Lingfeng <lilingfeng3@huawei.com> --- fs/smb/server/smb2pdu.c | 121 +++++++++++++++++++++++++++++----------- fs/smb/server/smbacl.c | 43 ++++++++++++++ fs/smb/server/smbacl.h | 2 + 3 files changed, 134 insertions(+), 32 deletions(-) diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c index 3681006c7ac8..ea7d467bd5cf 100644 --- a/fs/smb/server/smb2pdu.c +++ b/fs/smb/server/smb2pdu.c @@ -3369,20 +3369,24 @@ int smb2_open(struct ksmbd_work *work) KSMBD_SHARE_FLAG_ACL_XATTR)) { struct smb_fattr fattr; struct smb_ntsd *pntsd; - int pntsd_size, ace_num = 0; + int pntsd_size; + size_t scratch_len; ksmbd_acls_fattr(&fattr, idmap, inode); - if (fattr.cf_acls) - ace_num = fattr.cf_acls->a_count; - if (fattr.cf_dacls) - ace_num += fattr.cf_dacls->a_count; - - pntsd = kmalloc(sizeof(struct smb_ntsd) + - sizeof(struct smb_sid) * 3 + - sizeof(struct smb_acl) + - sizeof(struct smb_ace) * ace_num * 2, - GFP_KERNEL); + scratch_len = smb_acl_sec_desc_scratch_len(&fattr, + NULL, 0, + OWNER_SECINFO | GROUP_SECINFO | + DACL_SECINFO); + if (!scratch_len || scratch_len == SIZE_MAX) { + rc = -EFBIG; + posix_acl_release(fattr.cf_acls); + posix_acl_release(fattr.cf_dacls); + goto err_out; + } + + pntsd = kvzalloc(scratch_len, GFP_KERNEL); if (!pntsd) { + rc = -ENOMEM; posix_acl_release(fattr.cf_acls); posix_acl_release(fattr.cf_dacls); goto err_out; @@ -3397,7 +3401,7 @@ int smb2_open(struct ksmbd_work *work) posix_acl_release(fattr.cf_acls); posix_acl_release(fattr.cf_dacls); if (rc) { - kfree(pntsd); + kvfree(pntsd); goto err_out; } @@ -3407,7 +3411,7 @@ int smb2_open(struct ksmbd_work *work) pntsd, pntsd_size, false); - kfree(pntsd); + kvfree(pntsd); if (rc) pr_err("failed to store ntacl in xattr : %d\n", rc); @@ -5301,8 +5305,9 @@ static int smb2_get_info_file(struct ksmbd_work *work, if (test_share_config_flag(work->tcon->share_conf, KSMBD_SHARE_FLAG_PIPE)) { /* smb2 info file called for pipe */ - return smb2_get_info_file_pipe(work->sess, req, rsp, + rc = smb2_get_info_file_pipe(work->sess, req, rsp, work->response_buf); + goto iov_pin_out; } if (work->next_smb2_rcv_hdr_off) { @@ -5402,6 +5407,12 @@ static int smb2_get_info_file(struct ksmbd_work *work, rc = buffer_check_err(le32_to_cpu(req->OutputBufferLength), rsp, work->response_buf); ksmbd_fd_put(work, fp); + +iov_pin_out: + if (!rc) + rc = ksmbd_iov_pin_rsp(work, (void *)rsp, + offsetof(struct smb2_query_info_rsp, Buffer) + + le32_to_cpu(rsp->OutputBufferLength)); return rc; } @@ -5621,6 +5632,11 @@ static int smb2_get_info_filesystem(struct ksmbd_work *work, rc = buffer_check_err(le32_to_cpu(req->OutputBufferLength), rsp, work->response_buf); path_put(&path); + + if (!rc) + rc = ksmbd_iov_pin_rsp(work, (void *)rsp, + offsetof(struct smb2_query_info_rsp, Buffer) + + le32_to_cpu(rsp->OutputBufferLength)); return rc; } @@ -5630,13 +5646,14 @@ static int smb2_get_info_sec(struct ksmbd_work *work, { struct ksmbd_file *fp; struct mnt_idmap *idmap; - struct smb_ntsd *pntsd = (struct smb_ntsd *)rsp->Buffer, *ppntsd = NULL; + struct smb_ntsd *pntsd = NULL, *ppntsd = NULL; struct smb_fattr fattr = {{0}}; struct inode *inode; __u32 secdesclen = 0; unsigned int id = KSMBD_NO_FID, pid = KSMBD_NO_FID; int addition_info = le32_to_cpu(req->AdditionalInformation); - int rc = 0, ppntsd_size = 0; + int rc = 0, ppntsd_size = 0, max_len; + size_t scratch_len = 0; if (addition_info & ~(OWNER_SECINFO | GROUP_SECINFO | DACL_SECINFO | PROTECTED_DACL_SECINFO | @@ -5644,6 +5661,11 @@ static int smb2_get_info_sec(struct ksmbd_work *work, ksmbd_debug(SMB, "Unsupported addition info: 0x%x)\n", addition_info); + pntsd = kzalloc(ALIGN(sizeof(struct smb_ntsd), 8), + GFP_KERNEL); + if (!pntsd) + return -ENOMEM; + pntsd->revision = cpu_to_le16(1); pntsd->type = cpu_to_le16(SELF_RELATIVE | DACL_PROTECTED); pntsd->osidoffset = 0; @@ -5652,9 +5674,7 @@ static int smb2_get_info_sec(struct ksmbd_work *work, pntsd->dacloffset = 0; secdesclen = sizeof(struct smb_ntsd); - rsp->OutputBufferLength = cpu_to_le32(secdesclen); - - return 0; + goto iov_pin; } if (work->next_smb2_rcv_hdr_off) { @@ -5686,18 +5706,58 @@ static int smb2_get_info_sec(struct ksmbd_work *work, &ppntsd); /* Check if sd buffer size exceeds response buffer size */ - if (smb2_resp_buf_len(work, 8) > ppntsd_size) - rc = build_sec_desc(idmap, pntsd, ppntsd, ppntsd_size, - addition_info, &secdesclen, &fattr); + max_len = smb2_calc_max_out_buf_len(work, + offsetof(struct smb2_query_info_rsp, Buffer), + le32_to_cpu(req->OutputBufferLength)); + if (max_len < 0) { + rc = -EINVAL; + goto release_acl; + } + + scratch_len = smb_acl_sec_desc_scratch_len(&fattr, ppntsd, + ppntsd_size, addition_info); + if (!scratch_len || scratch_len == SIZE_MAX) { + rc = -EFBIG; + goto release_acl; + } + + pntsd = kvzalloc(scratch_len, GFP_KERNEL); + if (!pntsd) { + rc = -ENOMEM; + goto release_acl; + } + + rc = build_sec_desc(idmap, pntsd, ppntsd, ppntsd_size, + addition_info, &secdesclen, &fattr); + +release_acl: posix_acl_release(fattr.cf_acls); posix_acl_release(fattr.cf_dacls); kfree(ppntsd); ksmbd_fd_put(work, fp); + + if (!rc && ALIGN(secdesclen, 8) > scratch_len) + rc = -EFBIG; if (rc) - return rc; + goto err_out; +iov_pin: rsp->OutputBufferLength = cpu_to_le32(secdesclen); - return 0; + rc = buffer_check_err(le32_to_cpu(req->OutputBufferLength), + rsp, work->response_buf); + if (rc) + goto err_out; + + rc = ksmbd_iov_pin_rsp_read(work, (void *)rsp, + offsetof(struct smb2_query_info_rsp, Buffer), + pntsd, secdesclen); +err_out: + if (rc) { + rsp->OutputBufferLength = 0; + kvfree(pntsd); + } + + return rc; } /** @@ -5721,6 +5781,9 @@ int smb2_query_info(struct ksmbd_work *work) goto err_out; } + rsp->StructureSize = cpu_to_le16(9); + rsp->OutputBufferOffset = cpu_to_le16(72); + switch (req->InfoType) { case SMB2_O_INFO_FILE: ksmbd_debug(SMB, "GOT SMB2_O_INFO_FILE\n"); @@ -5741,14 +5804,6 @@ int smb2_query_info(struct ksmbd_work *work) } ksmbd_revert_fsids(work); - if (!rc) { - rsp->StructureSize = cpu_to_le16(9); - rsp->OutputBufferOffset = cpu_to_le16(72); - rc = ksmbd_iov_pin_rsp(work, (void *)rsp, - offsetof(struct smb2_query_info_rsp, Buffer) + - le32_to_cpu(rsp->OutputBufferLength)); - } - err_out: if (rc < 0) { if (rc == -EACCES) @@ -5759,6 +5814,8 @@ int smb2_query_info(struct ksmbd_work *work) rsp->hdr.Status = STATUS_UNEXPECTED_IO_ERROR; else if (rc == -ENOMEM) rsp->hdr.Status = STATUS_INSUFFICIENT_RESOURCES; + else if (rc == -EINVAL && rsp->hdr.Status == 0) + rsp->hdr.Status = STATUS_INVALID_PARAMETER; else if (rc == -EOPNOTSUPP || rsp->hdr.Status == 0) rsp->hdr.Status = STATUS_INVALID_INFO_CLASS; smb2_set_err_rsp(work); diff --git a/fs/smb/server/smbacl.c b/fs/smb/server/smbacl.c index 07d31dee99c0..b7818241e295 100644 --- a/fs/smb/server/smbacl.c +++ b/fs/smb/server/smbacl.c @@ -915,6 +915,49 @@ int parse_sec_desc(struct mnt_idmap *idmap, struct smb_ntsd *pntsd, return 0; } +size_t smb_acl_sec_desc_scratch_len(struct smb_fattr *fattr, + struct smb_ntsd *ppntsd, int ppntsd_size, int addition_info) +{ + size_t len = sizeof(struct smb_ntsd); + size_t tmp; + + if (addition_info & OWNER_SECINFO) + len += sizeof(struct smb_sid); + if (addition_info & GROUP_SECINFO) + len += sizeof(struct smb_sid); + if (!(addition_info & DACL_SECINFO)) + return len; + + len += sizeof(struct smb_acl); + if (ppntsd && ppntsd_size > 0) { + unsigned int dacl_offset = le32_to_cpu(ppntsd->dacloffset); + + if (dacl_offset < ppntsd_size && + check_add_overflow(len, ppntsd_size - dacl_offset, &len)) + return 0; + } + + if (fattr->cf_acls) { + if (check_mul_overflow((size_t)fattr->cf_acls->a_count, + 2 * sizeof(struct smb_ace), &tmp) || + check_add_overflow(len, tmp, &len)) + return 0; + } else { + /* default/minimum DACL */ + if (check_add_overflow(len, 5 * sizeof(struct smb_ace), &len)) + return 0; + } + + if (fattr->cf_dacls) { + if (check_mul_overflow((size_t)fattr->cf_dacls->a_count, + sizeof(struct smb_ace), &tmp) || + check_add_overflow(len, tmp, &len)) + return 0; + } + + return len; +} + /* Convert permission bits from mode to equivalent CIFS ACL */ int build_sec_desc(struct mnt_idmap *idmap, struct smb_ntsd *pntsd, struct smb_ntsd *ppntsd, diff --git a/fs/smb/server/smbacl.h b/fs/smb/server/smbacl.h index 2b52861707d8..64e6f8ebb68e 100644 --- a/fs/smb/server/smbacl.h +++ b/fs/smb/server/smbacl.h @@ -210,6 +210,8 @@ int set_info_sec(struct ksmbd_conn *conn, struct ksmbd_tree_connect *tcon, bool type_check, bool get_write); void id_to_sid(unsigned int cid, uint sidtype, struct smb_sid *ssid); void ksmbd_init_domain(u32 *sub_auth); +size_t smb_acl_sec_desc_scratch_len(struct smb_fattr *fattr, + struct smb_ntsd *ppntsd, int ppntsd_size, int addition_info); static inline uid_t posix_acl_uid_translate(struct mnt_idmap *idmap, struct posix_acl_entry *pace) -- 2.52.0